Improvement iw burglar-alarms



A. P. SILVA, R. B. MERRIAM & E. SED'GWICK.

Burglar-Alarm.

Patented July 20,1875.

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ALBERT P. SILVA, RUSSELL B. MERRIAM, AND EDW'IN SEDGVVIGK, OF

BINGHAMTON, NEW YORK.

IMPROVEMENT IN BURGLAR-ALARMS.

Specification forming part of Letters Patent No. E65,69H, dated July 20, 1875; application filed March 12, 1875.

To all whom it may concern:

Be it known that we, ALBERT P. SILVA, RUssELL B. MERRIAM, and EDWIN SEDG- WICK, all of Binghamton, in the county of Broome and State of New York, have invented a new and useful Improvement in 00111- bined Door-Knob Alarm and Door-Bell, which improvement is fully set forth in the following specification, reference being had to the accompanying drawings.

The object of our invention is to producea cheap, convenient device, and one whieh' shall be neat and tasteful in appearance.

Figure 1 is a perspective view of the device with the bell and a portion of the casing removed. Fig. 2 is a side elevation, partly in section. Fig. 3 is a detached view of the cam and the sliding jointed pawl which actuates it,

and Figs. 4 and 5 are additional views of the pawl.

A is the door-knob, the spindle of which passes through the door, and is secured to the cylinder 0, which carries the face-plate 0, the bell A being screwed to plate 0, and covered by a shield, A which may be made of metal and of ornamental design. D is a cam or ratchet mounted upon plate 0, and provided with an arm, a, projecting underneath the tongue spring I). g is a link connecting cam D with the bent lever h, which carries the hammer. E is a plate or bar arranged within cylinder 0 on a line parallel with the spindle A. The shank of this bar passes through plate 0, and has pivoted to it the pawl d, which engages with the shoulder of a notch, 0, cut in the disk of the ratchet D. F is a T- shaped lever, pivoted at e. G is a disk provided with a circular recess which receives the end of cylinder 0. One arm of lever F passes through a slot, f, in the face B of the disk G. H is a second disk secured to the door and recessed to receive disk G. I is a pin sliding in disk G, there being a hole in disk H, into which this pin may be inserted when required.

The operation of the device is as follows: Supposing the parts to be in the position shown in Figs. 1 and 2, if the knob A be turned the bar E and lever F will describe an arc of a circle, of which the spindle A is the center, and as the inner end of lever F is restricted in its movement by the slot f, said lever will be moved into the position in which it is shown in Fig. 3, thus thrusting the pawl d outward from the face of plate 0 against the shoulder 'of the notch o, and rocking the ratchet upon its axis until the pawl escapes from the notch, when the spring I), pressing upon arm a, will return the ratchet to its original position, as in Fig. 3. When the knob A is returned to its original position the sliding bar E, pivoted pawl d, and lever F will also be replaced in the position shown in Fig. 1 by the action of spring 2', as will be readily understood from an inspection of the drawings. As the knob is turned and the ratchet rocked by pawl (Z, as above set forth, link g retracts the hammer, and when the pawl escapes from notch c, and the ratchet is returned to place by spring I), the hammer is made to strike the bell. Pin I may be withdrawn from disk H, when disk G will rotate with the spindle A and cylinder 0, so that the lever F and its striking mechanism will not be actuated; hence no alarm will be sounded when the door is opened.

What we claim is 1. The combination of the disks G H, lever F, pawl d, sliding bar E, and springs i and b with the ratchet D for actuating the hammer, substantially as set forth.

2. In combination with the lever F, sliding plate E, cam D, and the disks G H, the sliding pin I, substantially as set forth.

ALBERT P. SILVA. RUSSELL B. MERRIAM. EDWIN SEDG\VIGK.

Witnesses:

J. (3. ROBIE, I H. C. MERRIQK. 

